杉林红壤的供P缓冲性与P肥需要量研究

采用等温吸附试验方法对福建杉木林下红壤的供P缓冲性与P肥需要量进行研究。结果表明 :杉林红壤对P的吸附作用强、吸附量大 ,当土壤加P量为 6 0 0mg·kg- 1时 ,P的吸附量为 4 5 1.2　5 5 0 .8mg·kg- 1,吸附率高达 75 .2 %　 91.8%。土壤P的吸附反应自由能 (△G)和最大缓冲容量 (Mb)是评价土壤供磷缓冲性状的重要参数 ,它们与土壤理化性质关系较为密切 ,一般与pH、吸湿水及粘粒含量呈正相关 ,而与有机质、有效P及全P含量呈负相关。根据土壤P的吸附和供P缓冲性预测土壤需P量 ,对合理施用P肥更具意义

Study on the Phosphate Buffering Capacity and Fertiphos Requirement of Red Soils under Chinese Fir Stand

The phosphate buffering capacity and fertiphos requirement of red soils under Chinese fir ( Cunninghamia Lanceolata) stand in Fujian province are studied. The results obtained by the experiments of isothermal phosphate adsorption show that the red soil can adsorb large amount of phosphorus.Phosphorus could be adsorbed firmly by the soil,so it will decrease the availability.When the amount of phosphorus added in the soils is 600 mg·kg^-1, the amount of phosphorus adsorbed by soils is 451.2 550.8 mg·kg^-1,its rate of phosphorus adsorbed is 75.2% 91.8%.The maximum buffering capacity and the free energy of phosphate adsorption are regarded as important indexes to evaluate the phosphate buffering capacity of soils. Regression analysis revealed that the maximum buffering capacity and free energy of phosphate adsorption has close relation to chemical and physical properties of soils.They generlly have positive relation to the pH value,the amount of clay and hygroscopic water of the soil.But they have negative relation to the contents of organic matter,available phosphate and total phosphate of the soil.Results also show that the fertiphos requirement of soil can be forecasted according to the phosphate adsorption and buffering capacity. It is significant for rational application of fertiphos.